trusty relate jobs are useless in post pipeline

kolla-dsvm-build.* related jobs only run since ocata cycle and trusty is
not supported since ocata by Kolla. So remove it in post pipeline.

Change-Id: Ifeff872b23eccd40c044233aacd38b73351b7b44

jenkins/jobs/kolla.yaml

@@ -66,9 +66,7 @@
     jobs:
       - 'kolla-dsvm-build-{distro}-{type}-{node}{suffix}':
           distro: ubuntu
-          node:
-            - ubuntu-trusty
-            - ubuntu-xenial
+          node: ubuntu-xenial
       - 'kolla-dsvm-build-{distro}-{type}-{node}{suffix}':
           distro:
             - centos

zuul/layout.yaml

@@ -11061,8 +11061,6 @@ projects:
     post:
       - kolla-dsvm-build-centos-binary-centos-7
       - kolla-dsvm-build-centos-source-centos-7
-      - kolla-dsvm-build-ubuntu-binary-ubuntu-trusty
-      - kolla-dsvm-build-ubuntu-source-ubuntu-trusty
       - kolla-dsvm-build-ubuntu-binary-ubuntu-xenial
       - kolla-dsvm-build-ubuntu-source-ubuntu-xenial
       - kolla-dsvm-build-oraclelinux-binary-centos-7